Tracks

On Network Rail lines, ref=* can hold the Engineer's Line Reference (ELR). For instance ref=MLN1 or ref=BGK. This is usually marked on bridges and level crossings. An ELR and mileage together define a location on the Network Rail network.

“Light” railways

Many railways in Great Britain have names ending in “Light Railway” because they were authorised under the Light Railways Acts 1896 and 1921. That doesn’t necessarily mean that they should be tagged railway=light_rail: most of them are operated like main-line railways and should be tagged railway=rail or railway=narrow_gauge.

Tunnels

Tunnels on Network Rail infrastructure usually have names displayed along with the length of the tunnel at the tunnel portals. This can be tagged as tunnel:name=*.

Main Signals

light main signal (combined lenses)

light main signal (individual lenses) with a junction signal

light main signals (combined) with junction signals (open this image and zoom in)